From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: [PATCH][v2] timekeeping: Fix memory overwrite of sleep_time_bin array Date: Tue, 19 Jul 2016 10:36:20 +0200 (CEST) Message-ID: References: <1468903861-12487-1-git-send-email-yu.c.chen@intel.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <1468903861-12487-1-git-send-email-yu.c.chen@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Chen Yu Cc: John Stultz , "Rafael J. Wysock" , Linux PM list , Linux Kernel list , "Stable # 3 . 17+" List-Id: linux-pm@vger.kernel.org On Tue, 19 Jul 2016, Chen Yu wrote: > It is reported the hibernation fails at 2nd attempt, which > hangs at hibernate() -> syscore_resume() -> i8237A_resume() > -> claim_dma_lock(), because the lock has already been taken. > However there is actually no other process would like to grab > this lock on that problematic platform. > > Further investigation shows that, the problem is caused by setting > /sys/power/pm_trace to 1 before the 1st hibernation, since once > pm_trace is enabled, the rtc becomes an unmeaningful value after resumed, So why is the RTC value useless if pm_trace is enabled? I really have a hard time to understand why pm_trace would affect the sleep time readout from RTC. Thanks, tglx